Starfire GT50 engine fires up but stalls prematurely

[Pablo]

As the old timer mechanics say, start with all the basics first.....fuel, spark, compression, timing.....

If I were to just throw something out there (AND i AM JUST THROWING IT OUT), it doesn't sound like your needle is properly tapered. IF THE PROBLEM CONTINUES AFTER GOING THROUGH A TANK OR TWO OF FUEL - Pull the needle/slide assembly out of the top of the carb and look at the taper. The taper itself should not be sharp (of course the tip is sharp) - it should be a nice gradual slope. If you are skilled you can re-taper it so very slightly in a power drill with emery paper. But DON'T GO SANDING ON YOUR NEEDLE UNLESS YOU ARE CERTAIN THE TAPER IS NOT CORRECT.

YOU DO NEED TO BE AWARE THESE ENGINES TAKE QUITE SOME TIME TO BREAK IN AND WILL GAIN POWER IF ALL TUNING IS CORRECT.

Riddle me this 1: What does your plug look like after a run?

Riddle me this 2: Do you see any leakage around the plug or head gasket?

 

[motorpsycho]

its **** impossible to crank the wheel and hold a spark plug.. Or ride and hold a spark plug attached to a tiny cable.

no it isn't. If your bike has a side kick stand, just lean the bike over on the stand enough to get the rear wheel off the ground. let the bike lean on your shoulder & the kickstand will hold the rear wheel off the ground. while kneeling down next to the bike, spin the rear wheel with your hand.
with the spark plug out of the cylinder, the engine will spin over fairly easy since there is no compression. connect the wire to the spark plug, and rest the plug on the cylinder head where you can see the electrode.

 

[motorpsycho]

heh yeah I know, I mentioned in a previous post that I noticed a lot of sediment in my fuel line and had to drain it and rinse my tank out.

I'm using an NGK Spark plug of some variety (came with two in the kit), im having a lot of trouble testing them however as its **** impossible to crank the wheel and hold a spark plug.. Or ride and hold a spark plug attached to a tiny cable.

The fact that nothing seems to come out at all when I crank it with no plug in indicate to me that its the carby, however the **** thing is screwed on with the screws upside down for absolutely no reason, making them inaccessible except with a right angle screwdriver thing. So incredibly dumb. Good old chinese engineers.

There might be some vapour comming out though, its hard to tell without literally sticking a nostril to the plug hole.. which seems like a bad idea.

I've tried it in every possible choke combination to no avail. Also unsure as to which way the little white thing is supposed to face (up or sideways) so ive had to try everything twice..... Nothing mentioned in the manual about this at all.

Sigh. After nearly 2 months working on it, I just want to have one decent freaking ride.

this may sound stupid, but you do have the gas turned on right? some of these have 2 gas valves, one on the tank and one directly on the carb (this is how mine is). the one on the carb is a white plastic T. It should be turned so that the top of the T is in line with the gas line.
More than likely, you have this valve closed, and no fuel is getting into the carb.

 

[Hajuu]

I'll check those two things tomorrow..

As for the rest, It could very well even be just the actual power of the engine, who knows.

It was mainly the shudder that was slightly annoying to me, but even that is mainly annoying because I dont have any gears on my bike, meaning that every time I slow down I have quite a hard time of pedalling to begin with. Tomorrow I might hard set my read derailleur to a lower gear since the high speeds dont really need assistance (I set it to a medium gear combo so I could have my pedals have an effect while using the engine but could still start the thing).

 

[Hajuu]

On another note (A smaller issue that is consistent with my chain)

Hey guys

another small issue ive been consistently having is, every time I take my chain off for whatever reason, I have immense issues with getting my master chain link back on.

One side of the coupling pin thing always comes out a little less far than the other side, although the entire thing is sitting flush, with no grime or grease.

I've already replaced the chain once, and now upon trying to put my chain back on when repairing my fuel leak problem (from the previous thread), im having the same problem again..

Each time, the new chain goes on quickly and easilly with no issues with the master chain link, but it's really very very annoying trying to clip on a master link clip to something that just wont extend far enough, for no forseeable reason.

Any ideas?

Cheers,
Hajuu

 

[professor]

Squeeze the link together with something before you try to put the clip in.

 

[Hajuu]

*shrug* yeah we tried that last time before I bought a new chain, in his workshop. Short of maybe using a vice (which would be practically impossible), we were unable to get it on, and even tried to grind down the outer pieces of the link on both sides, both ends with a hand file.. no luck. no idea how its even possible, as the back of the master link sits flush with both ends, yet one end always ends up protruding not far enough to use the clip..

Pretty majorly annoying

 

[Hajuu]

Replaced bucking bar, seems to have a throttling problem of some description now

Hey guys,

I just machined myself up a new bucking bar out of a hardened drill bit end (perfect width), which has allowed my clutch to work acceptably for now (ive ordered a replacement).

However, now it starts, and runs, as long as I keep pedaling quite hard, but even though while pedaling hard it runs, the throttle seems to suddenly have zero effect..

The throttle cable also seems very loose all the sudden, almost coming out of the end of the throttle attachment thing (on the hand grip).. When I twist it it seems like its perhaps sending slightly more fuel, but I have absolutely zero power.

The throttle cable attachment in the carb seems to move freely as normal if I pull lightly on the cable.. Any ideas? Could it possibly be the clutch slipping?

The original problem was with the fuel bung on the carb (the little white turning thing) which was leaking quite badly, now if I put my finger on the open part of the gasket at the bottom, my finger DOES come away with fuel on it, but its not dripping or anything at all..

My dealer at his workshop took it apart and flattened the gasket and cleaned it, checked the inner seal was intact, and reassembled it using bolts and a couple of nuts, which seemed to fix the problem completely at the time, but somewhere along the way I lost my bucking bar..

Any ideas?

Cheers,
Hajuu

 

[AussieSteve]

Doesn't sound like the clutch slipping. Are the cable casing adjusters on each end of your throttle cable adjusted correctly? Sounds like one or both are too loose.
If you remove the air cleaner you should be able to see the carb slide. See if it's at the bottom with the throttle released and pulls right to the top with the twist-grip at WOT.
If it doesn't pull right to the top, adjust the cable sheath until it does.
It's best to still leave about 2-3mm of slack in the cable casing, to allow for movement of the handlebars from side to side.

... Steve

 

[Hajuu]

Hm alright ill check it out... Cause it is sounding like its running ok, not a hint of spluttering or anything....